Such technical chains serve to transmit forces and movements. The above described bush chains, in which the chain hinge is formed by a bush and a pin attached thereto, as well as roller chains, in which an additional roller is arranged on the bushes, are used e.g. in chain drives and transmit torque and power. Fields of use are e.g. internal combustion engines, in particular the timing drive.
Bush chains consist of inner chain links and outer chain links which are offset relative to said inner chain links. The inner chain links normally comprise two inner link plates which each have two link plate openings. The bushes are press-fitted into the link plate openings and thus connect the two inner link plates. The outer chain links each comprise two outer link plates which also have two link plate openings each. The link plate openings of the outer chain links have inserted therein respective pins, said pins connecting the two outer link plates in this way. For connecting the inner chain links with the outer chain links, the pins are conducted through the bushes of the inner chain links, the outer chain links being offset relative to the inner chain links. In order to allow a larger chain width, also two or a plurality of these chains may be arranged in parallel and connected to one another.
One drawback of bush chains is that the bushes come again and again into contact with the same surfaces of the associated chain wheels, whereby an increased amount of wear occurs. It is therefore known to provide additional rollers on the bushes, which can rotate on said bushes. These so-called roller chains lead to a reduction of wear on the bushes.
Another drawback of the known bush and roller chains is the friction occurring, which leads to an increase in CO2 emissions, when these chains are used in internal combustion engines.
Known solutions for reducing the friction in the case of bush or roller chains with conventional pin joints are e.g. the application of a friction-reducing coating to the individual components of a chain, cf. e.g. DE 10 2006 052 869 A1 or DE 20 2006 015 821 U1, or a reduction of the size of the contact surfaces between link plates and other interfaces, such as the tensioning rails or the guide rails.
DE 42 35 198 A1 describes a bush or roller chain in which the chain links are interconnected by means of rocker joints. The bushes of the rocker joints have a constant wall thickness and are provided with a recess on one side thereof, said recess defining a first rocker surface in the bush. The pins of the rocker joints define the second rocker surface.